Filevault2 on Secondary Volume

[haralds]

This might be useful to anybody setting up Filevault2 on a second volume:

Setting up a new volume vs one that already contains a bunch of files does not seem to make a difference!

I erased everything, then set up Filevault2 in the hope it would traverse empty blocks quickly. But it looks like it separately encrypts every block.

There is no point in erasing,

 

[simonsi]

The whole point is no-one is able to scan the disk and recover files so yes it has to encrypt everything on the volume I would have thought, data and empty space included.

Just to add - FV2 works that way because it is volume-level encryption, if you were using file-level and encrypting only the files on the disk of course that would not encrypt empty space so would be quicker on initial setup...

 

[mannyo1221]

The empty blocks are also encrypted because even though the disk contains nothing, the blocks may contain previous data. Windows PC based disc encryption does exactly the same thing, it took 24 hours to encrypt a 500GB windows volume that had nothing on it except a windows install.